import re
import json

str1 = 'fetchJSON_comment98({"productAttr":null,"productCommentSummary":{"skuId":100016034388,"averageScore":5,"defaultGoodCount":0,"defaultGoodCountStr":"20万"}});'

res = re.match("(fetchJSON_comment98\()(.*)(\);)", str1)
print(res.group(0))
print(res.group(1))
print(res.group(2))
print(res.group(3))

dict1 = json.loads(res.group(2))
print(dict1)
print(type(dict1))
print(dict1['productCommentSummary']['skuId'])